You can achieve something akin to this by rigging a cat frame using the NRS "Retro" downbars. They can be moved in and out on the upper frame crosstubes, to give you some adjustability for tube width.
There are some limits to how far in and out you can go. But I've got one like this that is reasonably flexible -- it can provide as much as 72" equivalent width, and it goes down to about 60" width as well. The limiting factor is how much you will tolerate the top portion of the frame being off-center. IIRC, my basic width is 66", which allows me to go about 6" each way. But I use it with 16'/25" NRS tubes, so they allow a bit more off-center than smaller diameter tubes would.